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arm64: vdso: remove commas between macro name and arguments
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LLVM's integrated assembler appears to assume an argument with default
value is passed whenever it sees a comma right after the macro name.
It will be fine if the number of following arguments is one less than
the number of parameters specified in the macro definition. Otherwise,
it fails. For example, the following code works:

$ cat foo.s
.macro  foo arg1=2, arg2=4
        ldr r0, [r1, #\arg1]
        ldr r0, [r1, #\arg2]
.endm

foo, arg2=8

$ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o
arm-linux-gnueabihf-objdump -dr ias.o

ias.o:     file format elf32-littlearm

Disassembly of section .text:

00000000 <.text>:
   0: e5910001 ldr r0, [r1, OnePlusOSS#2]
   4: e5910003 ldr r0, [r1, OnePlusOSS#8]

While the the following code would fail:

$ cat foo.s
.macro  foo arg1=2, arg2=4
        ldr r0, [r1, #\arg1]
        ldr r0, [r1, #\arg2]
.endm

foo, arg1=2, arg2=8

$ llvm-mc -triple=armv7a -filetype=obj foo.s -o ias.o
foo.s:6:14: error: too many positional arguments
foo, arg1=2, arg2=8

This causes build failures as follows:

arch/arm64/kernel/vdso/gettimeofday.S:230:24: error: too many positional
arguments
 clock_gettime_return, shift=1
                       ^
arch/arm64/kernel/vdso/gettimeofday.S:253:24: error: too many positional
arguments
 clock_gettime_return, shift=1
                       ^
arch/arm64/kernel/vdso/gettimeofday.S:274:24: error: too many positional
arguments
 clock_gettime_return, shift=1

This error is not in mainline because commit 28b1a824a4f4 ("arm64: vdso:
Substitute gettimeofday() with C implementation") rewrote this assembler
file in C as part of a 25 patch series that is unsuitable for stable.
Just remove the comma in the clock_gettime_return invocations in 4.19 so
that GNU as and LLVM's integrated assembler work the same.

Link:
ClangBuiltLinux/linux#1349

Suggested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jian Cai <jiancai@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: I7eea04241c1f8ac7bc3b7915b781acdd1e2b6686
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jcai19 authored and DarkJoker360 committed Oct 12, 2022
1 parent 2428b90 commit 17ba508
Showing 1 changed file with 3 additions and 3 deletions.
6 changes: 3 additions & 3 deletions arch/arm64/kernel/vdso/gettimeofday.S
Original file line number Diff line number Diff line change
Expand Up @@ -220,7 +220,7 @@ realtime:
get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
get_ts_realtime res_sec=x10, res_nsec=x11, \
clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
clock_gettime_return, shift=1
clock_gettime_return shift=1

ALIGN
monotonic:
Expand All @@ -243,7 +243,7 @@ monotonic:
clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9

add_ts sec=x10, nsec=x11, ts_sec=x3, ts_nsec=x4, nsec_to_sec=x9
clock_gettime_return, shift=1
clock_gettime_return shift=1

ALIGN
monotonic_raw:
Expand All @@ -264,7 +264,7 @@ monotonic_raw:
clock_nsec=x15, nsec_to_sec=x9

add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
clock_gettime_return, shift=1
clock_gettime_return shift=1

ALIGN
realtime_coarse:
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